A vehicle can be equipped with deployable safety devices designed to reduce injury to a pedestrian struck by the vehicle. For example, the vehicle may be equipped with one or more pedestrian air bags and/or a device for changing the inclination angle of the hood. Since these devices are only to be deployed in the event of a pedestrian impact, the deployment system must be capable of reliably distinguishing pedestrian impacts from abuse events (such as hammer blows to the front bumper) and impacts with other objects. In this regard, it has been recognized that pedestrian impacts are nearly always characterized by two impacts: a first impact with the vehicle bumper followed by a second impact with the vehicle hood. Thus, the vehicle can be equipped with one or more bumper impact sensors and one or more hood impact sensors, as suggested in the U.S. Patent Publication No. 2002/0180596 A1, for example. However, equipping a production vehicle with the required sensors can be both costly and difficult. Moreover, it can be difficult to deploy the safety devices in time to effectively reduce pedestrian injury since the collision is only detected after the pedestrian strikes the hood. Accordingly, what is needed is a pedestrian impact detection method that is more practical and cost-effective and that provides earlier detection of the impact without sacrificing detection reliability.